The retina is the transparent, light-sensitive structure at the back of the eye. The cornea and lens focus light onto the retina. The central area of the retina, called the macula, contains a high density of color-sensitive photoreceptor (light-sensing) cells. These cells, called cones, produce the sharpest visual images and are responsible for central and color vision. The peripheral area of the retina, which surrounds the macula, contains photoreceptor cells called rods, which respond to lower light levels but are not color sensitive. The rods are responsible for peripheral vision and night vision.